Unformatted text preview: ader to make his or her own judgment about the strength of the evidence. NEXT STEPS In the previous example it is clear that the sample mean was very unlikely to have come from a population with a mean GPA of 2.50. When the P
value is larger (and thus observing the sample statistic is more likely), we use a cutoff to determine whether the sample statistic is “unusual enough”. The cutoff is called the level of significance and is abbreviated with the Greek letter α (alpha). © 2011 THE CARNEGIE FOUNDATION FOR THE ADVANCEMENT OF TEACHING A PATHWAY THROUGH STATISTICS, VERSION 1.6, STATWAY™
STUDENT HANDOUT STATWAY STUDENT HANDOUT  3 Lesson 8.2.2 Introduction to Hypothesis Testing YOU NEED TO KNOW Procedure for Comparing the P
value to α • When the P
value ≤ α, we say the evidence is strong enough to reject the null hypothesis and accept the alternative hypothesis. • When P
value > α, we say the evidence is not strong enough to reject the null hypothesis. We do not reject the null hypothesis and we do not accept the alternative hypothesis. This does not mean that the null hypothesis is true, since statistical data cannot be used to prove equality. For now we will use α = 0.05 as our level of significance. This means that if sample results at least as extreme as our sample statistic were to occur by chance less than 5% of the time, we would conclude that our sample supports the alternative hypothesis. In Topic 8.3 we will explore other levels of significance. TRY THESE 1 Consider this claim from the previous lesson: “More than half of all students at our college plan to vote in 2012.” Give the null and alte...
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 Spring '14

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